WASHINGTON (Reuters) - U.S. agents have raided the homes of five people who allegedly traded hundreds of thousands of songs, movies and other copyrighted material over the Internet, Attorney General John Ashcroft says.

Agents raided residences in Texas, New York and Wisconsin early on Wednesday and seized computers that they suspect were involved in a nationwide file-trading network.

The raids marked a sharp escalation of the years-long legal battle surrounding unauthorised copying over peer-to-peer, or P2P, networks.

Until now, the Justice Department has only pursued elite groups of hackers who steal and distribute movies, music and software before their official release dates.

Authorities made no arrests. But Ashcroft warned that those who copy music, movies and software over P2P networks without permission could face jail time.

"We do not believe it is appropriate for the Department of Justice to stand by while such theft is taking place," Ashcroft said at a press conference.

"P2P does not stand for 'permission to pilfer,'" Ashcroft said.

Targeted in the raids were people operating "hubs" in a file-sharing network based on Direct Connect software.

An official at Direct Connect parent NeoModus was not immediately available for comment.

In order to join the network, members had to promise to provide between one and 100 gigabytes of material to trade, or up to 250,000 songs, Ashcroft said.

"They are clearly directing and operating an enterprise which countenances illegal activity and makes as a condition of membership the willingness to make available material to be stolen," he said.

Each of the five hubs contained 40 petabytes of data, the equivalent of 60,000 movies or 10.5 million songs, Ashcroft said.

Among the files offered on the network were the movies "Kill Bill," "Lord of the Rings -- The Two Towers," and "The Last Samurai," according to an affidavit filed in connection with one of the search warrants.

Agents also searched an Internet service provider, but officials declined to specify which one and said it was not a target of the investigation.

Recording studios have waged an aggressive legal campaign against the networks and their users, but have also appealed to the Justice Department for help.

An appeals court in California affirmed last week that such networks can't be held responsible for illegal copying.

Record labels have brought more than 3,000 copyright lawsuits against individuals since last year, typically winning settlements of around $5,000 (2,780 pounds).

The Recording Industry Association of America on Wednesday announced it had sued another 744 individuals and refiled suits against 152 others who had ignored or declined offers to settle.